Electric contacting device for timepieces

ABSTRACT

An electric contacting device for timepieces wherein a first spring contact member is fixedly mounted at one end for periodic engagement by a second displaceable contact member at its other end. A vibration absorbing member is mounted on said first spring contact member adjacent the base thereof. The vibration absorbing member extends axially relative to the first spring contact member a distance equal to less than one-half the length of said first spring contact member.

' [76] Inventor:

United States Patent 1191 Inagaki 4] ELECTRIC CONTACTING DEVICE FOR TIMEPIECES Tokuichi Inagaki, 166-2, Hosokubo, Shiga,, Suwa, Japan 22 Filed: Oct.2l, 1971 211 Appl. No.: 191,391

[30] Foreign Application Priority Data Oct. 22, 1970 Japan 45/92514 [52] US. Cl. 58/28 A, 20/6l.39 [51] Int. Cl G046 3/04 [58] Field of Search 58/28 R, 28 A, 28 B, 28 D, 58/33; 206/16, 19, 61.39

[56] References Cited 9 UNITED STATES PATENTS 3,698,179 10/1972 Kaulins ..58/28R 1111 3,792,579 14 1 Feb. 19, 1974 Keeler et al 58/28 R Wuthrich 58/28 A l/l97l 9/1970 Primary Examiner-Richard B. Wilkinson Assistant ExaminerEdith Simmons Jackmon Attorney, Agent, or FirmBlum, Moscovitz, Friedman & Kaplan e [5 7] ABSTRACT An electric contacting device for timepieces wherein a first spring contact member is fixedly mounted at one end for periodic engagement by a second displaceable contact member at its other end. A vibration absorbing member is mounted on said first spring contact member adjacent the base thereof. The vibration absorbing member extends axially relative to the first spring contact member a distance equal to less than her.

4 Claims, 11 Drawing Figures I lllllllllll III II" IIIII I IIIIII Illl one-half the length of said first spring contact mem- 1 PATENT FEB 1 91974 sum 1 or 2 FIG! PATENTED FEB 1 9 m4 SHEU'B 0P2 FIG. 4'

FIG. 7

FIG. 5

FIG. a

FIG." 3 I FIG. 1/

FIG 9 FIG. 10 4 ELECTRIC CONTACTING DEVICE FOR TIMEPIECES BACKGROUND OF THE INVENTION This invention relates to an electric watch driven by the interrelation between a constant magnetic field and a pulsating field, and more particularly, to the improvement in the switch mechanism for producing said pulsating magnetic field. The electric watches in question may be classified into two-types. A first type includes a movable coil and a fixed magnet, while the second type includes a movable magnet and a fixed coil. In both types of devices, mechanically operated electric switches are provided. These switches intermittently connect the electric source, such as a battery, to the coil to produce the pulsating magnetic field which applies a driving force to the rotational member of the timepiece once or twice in each oscillating period by cooperating with a permanent magnet.

In such devices, the mechanical switch is closed about 2 X per year during normal usage. Accordingly, the precision of the watch may be deteriorated by the abrasion of said mechanical switch during each year of use. In addition to said abrasion, the contact point is affected by the spark caused by the make and break of the electric circuit. Usually one end of the contact member is attached to a spring to absorb the shock of contact. Contact is further affected by the natural transverse vibration caused by the shock on the fixed contact member and the mounting spring thereof at every closing of the contact point. Accordingly, before each complete operative closing of the contact point, the fixed and displaceable contact members are intermittently engaged in a vibratory manner. Said intermittent engagement occurs up to ten times during each operative closing of the contact point, so that said contact point is further abraded and sparking discharge occurs. Thisabrasion and sparking substantially shortens the life of the contact point.

Further, since the transverse vibration of the contact spring of the conventional arrangements cannot be fully damped during each cycle, the displaceable contact member may engage and lock against the end of the fixed contact member if, due to the vibration of said fixed contact member, said end is disposed in facing relation to the path of travel of said fixed contact. Such a circumstance, which is illustrated in FIG. 1 1, results in the locking of the balance wheel through the engagement between the fixed and displaceable contact members. SUMMARY OF THE INVENTION Generally speaking, in accordance with the invention, an electric contacting device for timepieces is provided including a first spring contact member fixedly mounted at one end, a second displaceable contact member mounted for oscillatory displacement relative to said first spring contact member for periodic engagement thereof, and a vibration absorbing member mounted on said first spring contact member adjacent the base thereof. Said vibration absorbing member is dimensioned to extend axially along said first spring contact member a distance equal to less than one-half the length of said first spring contact member.

Said second displaceable contact member may be mounted for oscillatory displacement on the balance wheel of said watch, said first spring contact member being positioned in the path of displacementof said second displaceable contact member. A nonconductive member is also mounted on said balance wheel adjacent said second displaceable contact member. Said non-conductive member is dimensioned to engage said first spring contact member immediately before engagement thereof by said second displaceable contact member for absorbing at least a portion of the initial contact viration.

Accordingly, it is an object of the present invention to provide an electrical contacting device for timepieces wherein the secondary vibration of the contact spring member is controlled.

A further object of the present invention is to provide an electric contacting device for timepieces which permits the efficient use of the period of engagement between the contact of said device, and therefore the efficient transmission of energy from the power source.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanyingdrawings, in which:

FIG. 1 is a side elevational sectional view of an electric timepiece according to the invention taken along line BB of FIG. 2;

FIG. 2 is a partial top plan sectional view taken along line A--A of FIG. 1, showing the principle electromechanical elements of the electric watch according to the invention;

FIGS. 3, 4, 5 and 6 sequentially depict the switching action of the contacting device according to the invention during one cycle;

FIGS. 7, 8, 9 and 10 depict various embodiments of the vibration absorbing means according to the invention; and

FIG. 1 1 depicts the consequences of the engagement of the end portion of the fixed contact member with the movable contact member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1 and 2, the balance wheel of the timepiece depicted is provided with an upper member 7a and a lower member 7b which are secured to an axis 1. Each of said upper and lower members 7a and 7b of said balance wheel have a pair of spaced permanent magnets secured thereto in facing relation to the permanent magnets on the other of said upper and lower members. Thus, permanent magnets 8a and 8c (not shown) are mounted on upper member 7a, while permanent magnets 8b and 8d are mounted on lower member 7b. A movable contacting member consisting of a non-conductive member 2 and a conductive contact point 3 is mounted on a flange of axis 1. Nonconductive member 2 is a jewel formed of a nonconductive material, while said contact point is formed of electrically conductive material and is electrically connected to the axis I. Said balance wheel is supported by bearings 10a and 10b and rotates in an oscillatory manner about the axis 1. Said balance wheel drives an escapement 21 by means of a roller jewel fixed to the upper member 7a, which in turn drives a gear train 22.

The balance wheel is provided with a hair spring 6, the inner end of which is fixed to a hair spring collet 5 mounted on axis 1. The outer ,end of said hair spring is fixed to a-stud 16, which is attached to the plate 14 of the watch. The inertia-of thp balance wheel and the length of the hair spring determine the oscillatory period thereof. Permanent magnets 8a, 8b, 8c and 8d are alternately polarized to define a magnetic circuit having a flux path passing between the respective permanent magnets mounted on upper member 7a and lower member 7b. A circular coil 9 is fixedly mounted by means of coil block 18 in the path of said magnetic flux intermediate said upper and lower members of said balance wheel. One tap of said circular coil is connected to the negative side of a power source, such as a bat- .tery, while the other tap of said circular coil is connected to a fixed spring contact member 4. Permanent magnets 8a, 8b, 8c and 8d, and the coil 9 are positioned so that the balance wheel is driven magnetically when movable contact point 3 and fixed spring contact member 4 are engaged. The engagement of said contact point and fixed spring contact closes an electrical circuit which includes battery 17 and coil 9. Spring contact member 4 is fixed at-one end to a fixed insulation block 18. When the circuit is closed, current flows from the positive terminal of battery 17 through plate 14, stud l6, hair spring 6, hair spring collet 5, axis 1, contact point 3, spring contact member 4, coil 9, and back to the negative terminal of battery '17. The contact point and spring contact member engage two times during each oscillator period of the balance wheel. I

A vibration absorbing member 12 is mounted on spring contact member 4 for the purpose of damping the operation therein. As more particularly shown in FIG. 2, said spring contact member is attached to a fixed insulation block 13. Spring contact member 4 consists of a leaf spring, of a length shorter than the distance L in FIG. 2. Said leaf spring is mounted on fixed insulation block 13 along a center line 13 aligned with the center of axis 1. Only one end of said contact spring member is fixed, the other end being freely displaceable in response engagement by non-conductive member 2 and contact pin 3 during the rotation of the balance wheel. The portion of spring contactmember 4 which engages against contact pin 3 acts as a contact point for the closing of the above-described electrical circuit.

Vibration absorbing member 12, which serves to damp the vibrations of said spring contact member, is mounted on said spring contact member in abutment with fixed insulation block 13. Said vibration absorbing member extends from said fixed insulation block a distance along said spring contact member equal to less than one-half of the length of said spring contact member.

Transverse secondary vibration is produced in the spring contact member immediately after said member is disengaged by the contact point 3. Vibration absorb.- ing member 12 controls said secondary vibration and stops said vibration in a short period of time due to the vibration absorbing characteristics of the material of which it is formed. Further, the loss of the energy necessary for bending the contact spring, which is included in the holding energy of the balance wheel assembly, which serves as a rotational oscillator, is not increased.

Referring now to FIGS. 3, 4, 5 and 6, the sequential operation of the contacting device according to the invention is depicted. FIG. 3 shows the arrangement disclosed immediately before engagement of the'contact members. The balance wheel rotates about axis 1 in the direction of arrow C, carrying with it non-conductive member 2 and contact point 3. Said non-conductive member engages spring contact member 4 starting the deflection thereof, as shown in FIG. 4. Said nonconductive member serves to absorb the initial shock of engagement with spring contactmember 4.

FIG. 5 shows contact point 3 in engagement with spring contact member 4 to close the above-described electric circuit so as to supply energy to the balance wheel. 'FIG. 6 shows 'thecontact point and nonconductive member carried beyond the contact spring member 4 by said balance wheel. Since the balance wheel oscillates, said non-conductive member and contact point will now be carried in the direction opposite to arrow C from the dead point of vibration to en gage contact spring 4 a second time to again close the electrical circuit. Said electrical circuit isopen during the period that said contact point and spring contact member are out of engagement. Hair spring 6 provides the force of restitution to the balance. wheel for the return of the balance wheel to its initial position, the electrical circuit, in cooperation with'the permanent magnets, serving to provide the driving force for sustaining said oscillation. The above-described cycleis repeated 7 once during each oscillation of the balance wheel.

Since the spring contact member is formed as a leaf spring, said member having the vibration and damping characteristics of a leaf spring. The use of such a leaf spring is dictated, in part, by the desire to minimize mechanical losses caused by the interaction of the displaceable contact point and the fixed spring contact member. Operative consideration such as the foregoing dictates that the leaf spring employed be both resilient and thin. However, the damping time of the secondary vibration of such thin leaf springs is relatively long, causing chattering of the contact. This chattering is avoided by the provision of the vibration absorbing member 12 according to the invention.

In one embodiment of the arrangement according to the invention spring contact member 3 is 10 mm. in length, 0.04 mm. in thickness, and 0.20 mm. in width, and has a natural damping time of about one-third second. Whensaid contact spring is provided with said vibration absorbing member, the vibration is damped and stops within one-twentieth second. Further, chatter is eliminated and the driving efficiency of the balance wheel is improved by about 30' percent.

Vibration absorbing member l2 may be mounted on spring contact member 4 in two ways. First, the material of which the vibration absorbing member is formed, either plastic or rubber, is deposited about the spring contact member while in the liquid state. In the second approach, the spring contact member is mounted on the vibration absorbing member after said vibration absorbing member is formed, while said member is at the nonnal temperature.

Thus, in the embodiment of FIG. 7, the vibration absorbing member is secured directly to the contact spring. In the embodiment of FIGS. 8 and 9, the fixed insulation block is formed with upstanding walls defining a channnel, the vibration absorbing member being formed by the adding of the plastic or rubber in a liquid state into said channel after the spring contact member is positioned.

In the embodiment of H0. 10, the vibration absorbing member is separately formed with an aperture therethrough for receiving said spring contact member, the securing of said vibration absorbing member being completed by heating or chemical action.

The mounting of the vibration absorbing member in any of the above-described embodiments is extremely easy, and results in a particularly advantageous arrangement.

It will thus be seen that the objects set forth above, among those made apparent from thepreceding description, are efficiently attained and, since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a lim- 'iting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is:

1. An electric contacting device for timepieces comprising an oscillatory balance wheel assembly having a central shaft, a pair of coaxial discs mounted on said shaft in spaced relation, and two pairs of permanent magnets mounted in overlapping relation on facing surfaces of said discs; a driving coil fixedly mounted in the gap between said pairs of permanent magnets between said discs; a first spring contact member fixedly mounted at one end thereof; a second displaceable contact member mounted on said balance wheel assembly for oscillatory displacement relative to said first spring contact member for periodic engagement therewith in the region of the other end of said first spring contact member; a damper member mounted on said first spring contact member adjacent said one fixed end thereof and extending from said one end along said first spring contact member a distance equal to less than one-half the length of said first spring contact member for absorbing the vibration of said first spring contact member after each engagement and disengagement from said second displaceable contact member, a battery and means electrically connecting said first and second contact members, said battery and driving coil in series for the application of driving current to said coil when said contact members are in engagement.

2. An electric contacting device as recited in claim 1, including a non-conductive member mounted on said balance wheel assembly adjacent said second displaceable contact member, said non-conductive member being dimensioned to engage said first spring contact member immediately before engagement thereof by said second displaceable contact member for absorbing at least a portion of the initial contact vibration.

3. An electric contacting device for timepieces as recited in claim 1, wherein said first spring contact member is a leaf spring.

4. An electric contacting device as recited in claim 4, wherein said damper member is formed of a material selected from the group consisting of resilient rubber and plastic.

UNITED STATES PATENT "OFFICE j CERTIFICATE OF CORRECTION Patent No. 3,792,579 Dated Feb. 1.9,. 1974 Inventor (x) Toku iChi Inagaki It is certified that error appears in the above-identified pateht and that said Letters Patent are hereby corrected as shown below:

Columh 6, 1ine'31, theclaim reference numeral "4" Should read --3--.

Signed end sealed this 7th day of January 1975.

(SEAL) Attestz;

McCOY M. GIBSON JR. I C. MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM-DC ooa-lo-po FORM PO-105O (10-69 s 1 1 u.s. eoiluuuzur munuc orrlc: nu o-au-sm UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo. 3,792,579 7 Dated Feb. 19,1974

InventorQs) Tokuichi Inagaki It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 31, the claim reference numeral "4" should read --3--.

Signed and sealed this 7th day of January 1975.

(SEAL) Attest:

GIBSON JR. c. MARSHALL DANN McCOY M Commissioner of Patents Attesting Officer FORM PC4050 (10459) uscoMM-oc Bean-Poo I 1L5. GOlIIRNHENT F RINTHNG OFFICE: I9. O-'3"-33" 

1. An eleCtric contacting device for timepieces comprising an oscillatory balance wheel assembly having a central shaft, a pair of coaxial discs mounted on said shaft in spaced relation, and two pairs of permanent magnets mounted in overlapping relation on facing surfaces of said discs; a driving coil fixedly mounted in the gap between said pairs of permanent magnets between said discs; a first spring contact member fixedly mounted at one end thereof; a second displaceable contact member mounted on said balance wheel assembly for oscillatory displacement relative to said first spring contact member for periodic engagement therewith in the region of the other end of said first spring contact member; a damper member mounted on said first spring contact member adjacent said one fixed end thereof and extending from said one end along said first spring contact member a distance equal to less than one-half the length of said first spring contact member for absorbing the vibration of said first spring contact member after each engagement and disengagement from said second displaceable contact member, a battery and means electrically connecting said first and second contact members, said battery and driving coil in series for the application of driving current to said coil when said contact members are in engagement.
 2. An electric contacting device as recited in claim 1, including a non-conductive member mounted on said balance wheel assembly adjacent said second displaceable contact member, said non-conductive member being dimensioned to engage said first spring contact member immediately before engagement thereof by said second displaceable contact member for absorbing at least a portion of the initial contact vibration.
 3. An electric contacting device for timepieces as recited in claim 1, wherein said first spring contact member is a leaf spring.
 4. An electric contacting device as recited in claim 4, wherein said damper member is formed of a material selected from the group consisting of resilient rubber and plastic. 